The present invention relates to a technique for measuring the three-dimensional profile of micropatterns formed in semiconductor memories, integrated operational circuits and other semiconductor devices.
As a technique for measuring the width of a micropattern formed in a semiconductor device, the length-measuring SEM (Scanning Electron Microscopy) is known which emits an electron beam and uses the amplitude of a signal obtained by detecting generated secondary electrons and reflected electrons. However, the length-measuring SEM cannot measure the height of a micropattern although it can measure its very small width. To measure the height, it is therefore necessary to cut the circuit pattern portion of concern in the semiconductor device and observe the cross section under an electron microscope or the like.
One example is disclosed in Japanese Patent Laid-open No. 74326/1999. Such a method cuts a wafer and observes a cross section by using, for example, an electron microscope to measure the height of a pattern. Once the wafer is cut, however, the damaged portions cannot be used to manufacture products. Also it is not sure that the observed portion of the semiconductor device maintains the same size and geometry as before it is cut. Further, such a method requires a long period of time for cutting and observation.